1. Technical Field
Aspects of this document relate generally to computer analysis systems and methods used for analyzing data from an industrial, manufacturing, or business processes and identifying process data exceptions.
2. Background Art
Data analysis systems are conventionally utilized in combination with many industrial and commercial processes to collect and process information coming from the process. Data analysis systems conventionally receive sensor data, equipment performance information, product property information, and other information about the process that may be useful if stored. Determining what data and which variables measured in the process affect process output are common uses for conventional data analysis systems.
Process data historians have existed for a number of years. Process data historians are provided by a number of different manufacturers, but they all interface with the user by displaying trend charts, current values, etc.
Process data historians collect and store data such as flows, temperature, pressures, and even vibration levels. Users can then display this historical data using trend charts, displaying real or historical values numerically or with symbols, even allow users to set alarm limits so that numerical values or symbols change color, flash, etc. when alarm limits are exceeded.
Alarms are a term generally used in manufacturing to identify issues that must be addressed. An example is a tank level; if the tank contains crude oil to be refined, for example, it would be useful to know if the tank is nearly empty or nearly full. An alarm point of 95, for example, would alert the operator that the tank is nearly full. Likewise, an alarm level of 5 would indicate the tank is nearly empty. Generally, once a process variable, in this case, a tank level, meets or exceeds the alarm limit, the alarm continues until acknowledged.
There are many problems with current alarm methods. In the example cited above, the oil refinery may have shut down to perform maintenance. Consequently, the tank level is 0 because it has been drained so that repairs may be made. Other problems occur if the limits on alarms are too restrictive; they then become what are commonly called “nuisance alarms.” Therefore, alarm limits are often so liberal that a problem is not identified in a timely manner.